1. Field of the Invention
The invention relates to the field of aircraft and, in particular, to a helicopter design.
2. Description of Related Art
Compound helicopters, having wings to provide lift during horizontal flight, loose efficiency during hover because of the disruption of downwash from the main rotor. This problem was addressed in U.S. Pat. No. 2,580,312 “Convertible Airplane And Helicopter” by H. K. Moore. Moore discloses an aircraft having a pusher propeller as well as a rotor. The wings of the airplane can be rotated from their leading edge downward, thus minimizing the effect of rotor downwash during vertical descent. However separate landing gear is required. Another approach is disclosed in U.S. Pat. No. 2,881,898 “Air Vehicle With Rotary Wing. By A. Flettner. Flettner discloses a compound helicopter type where in the wing tips of the wing are rotated downward by downwash of main rotor. During horizontal flight the lift forces produced by the wing tips to a horizontal position. The problem is that with no locking feature the wing tips will flutter. Furthermore, just rotating the wing tips will not significantly increase rotor efficiency during hover. Furthermore, separate landing apparatus is still required.
Thus, it is a primary object of the invention to provide a helicopter that incorporates wings for horizontal flight and which can be converted to landing struts.
It is another primary object of the invention to provide a helicopter that incorporates wings for horizontal flight and which can be converted to landing struts by rotating at least a portion of the wings downward so that they act as struts.
It is a further object of the invention to provide a helicopter that incorporates wings for horizontal flight and which can be converted to landing struts by rotating at least a portion of the wings downward so that they act as struts and provide minimum blockage of main rotor downwash during hover.